Coniston House, which is on the Chapel Ash island, has not been used since February last year.
It had most recently been used by around 500 Marston’s office workers who were moved in while the company's new headquarters were being built over the road next to the brewery.
Before that it had been used by the now defunct Wolverhampton Primary Care Trust.
Wolverhampton council has this week approved plans to make alterations to the building to facilitate its new use as residential apartments.
These include a new bin store, the installation of two security gates for the car park, a cycle shelter and new security fencing.
Documents submitted to the council by Tweedale Architects on behalf of the building's owner state work on converting the building has begun.
Michael Bates, Director at the firm, said: "The building's owners, Blackacres Limited, have now begun the initial works that will see the building converted to residential use for some 42 apartments."
Currently vehicles can be parked at street level with the building's three floors situated above. Plans for the conversion state 51 spaces will be retained, including three disabled bays.
The cost of Marston's new headquarters were put at ‘nearly £10 million’ by boss Ralph Findlay and the rebuild was completed over one year.